This apparatus relates to centrifugal clutches and more particularly relates to a novel and improved centrifugal clutch which is capable of manual and automatic control of the maximum pressure exerted on the clutch plates when moved into the engaged position as well as the amount of pressure required to disengage the clutch plates.
We have previously devised centrifugal clutches of the type having a plurality of cam members or balls which will move outwardly in response to rotation of a drive shaft to force a plurality of clutch plates into engagement with one another. In certain applications, such as, motorcycle clutches it is important to generate sufficient centrifugal force to clamp the clutch plates together without substantial slippage and without utilizing a larger sized case which exceeds the space allowances within a stock or standard engine case. Space is at a particular premium in motorcycle clutches incorporating a manual override mechanism, such as, set forth in hereinbefore referred to U.S. application Ser. No. 10/327,160 for MULTI-ROW CAM-ACTUATED CENTRIFUGAL CLUTCH. Further, it is desirable to incorporate into the end of the clutch case between the cover and pressure plate a pressure control mechanism which will combine the features of an automatic clutch with the performance of a traditional manual clutch so that the clutch can engage smoothly without the use of a clutch lever at low speeds but at the same time limit the axial force transmitted to the clutch plates by the cam members at higher speeds. In addition, it is highly desirable that the pressure control mechanism cooperate with the manual override lever in such a way as to minimize the hand pressure required to override the cam members and effectively operate as a conventional manual clutch with relatively light feel or manual pressure and yet be capable of operating within the same space limitations as the standard or stock motorcycle clutches.